Patent application title: Apparatus for detecting the travel of a lifting motor

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Abstract:

An apparatus for detecting the travel of a lifting motor, comprising: a
transmission unit positioned within a housing and having a reduction
gearset and a transmission gear meshed with the reduction gearset; a
threaded rod passing through a housing and threadedly coupled with the
transmission gear. The transmission unit includes at least one magnet at
one of the gears made of non-permeable material. The magnets are rotated
clockwise or counterclockwise with the non-permeable gear when the
transmission unit is driven by the motor in rotation. The number of
rotation will be detected by a magnetic sensor disposed at the housing
through the magnetic line of force generated by the magnet. Thereafter,
the detection signals will be transmitted to a travel-calculation unit
for measuring the linear displacement distance (travel) of the threaded
rod in axial direction. In this way, the built-in detecting structure
includes an integral arrangement and is easily secured to the treadmill.
Moreover, the external interference may be reduced to enhance the
precision and to prolong the service life.

Claims:

1. An apparatus for detecting the travel of a lifting motor, comprising:a)
a housing consisting of a front housing and a rear housing;b) a
transmission unit positioned within the housing and having a reduction
gearset and a transmission gear meshed with the reduction gearset;c) a
motor positioned at the external side of the housing, a driving shaft of
the motor being extended into the housing for driving the reduction
gearset;d) a threaded rod passing through the housing and threadedly
coupled with the transmission gear; ande) a fixing sleeve mounted at the
external side of the housing and fitting over one end of the threaded
rod;wherein the transmission unit includes at least one magnet at one of
the gears made of non-permeable material, and wherein the magnets are
rotated clockwise or counterclockwise with the non-permeable gear when
the transmission unit is driven by the motor in rotation, and wherein the
number of rotation will be detected by a magnetic sensor disposed at the
housing through the magnetic line of force generated by the magnet,
whereupon the detection signals will be transmitted to a
travel-calculation unit for measuring the linear displacement distance
(travel) of the threaded rod in axial direction.

2. The apparatus for detecting the travel of a lifting motor as recited in
claim 1 wherein the non-permeable gear fitted with the magnets is the
transmission gear.

3. The apparatus for detecting the travel of a lifting motor as recited in
claim 1 wherein the non-permeable gear fitted with the magnets is the
reduction gearset.

Description:

BACKGROUND OF THE INVENTION

[0001]1. Field of the Invention

[0002]The invention relates to an apparatus for detecting the travel of a
lifting motor, and more particularly to a structure having magnets
disposed at a built-in gear for detecting the number of rotation by use
of the magnetic line of force, thereby determining the lifting travel.

[0003]2. Description of the Related Art

[0004]A great number of motors are existing in the market. They are
differently designed according to various requirements. As shown in FIG.
1, a lifting motor 10 for a treadmill primarily includes a housing 11 in
which a transmission gear (not shown) is disposed. A motor 12 is employed
for providing the driving power with which the transmission gear imparts
motion to a transmission rod 14 for an axial movement within a sleeve 13.
In this way, the inclination of a treadmill's platform 20 relative to a
base frame 30 may be adjusted. In other words, the inclination angle of
the platform 20 is adjustable to meet different requirements of operators
on the inclination of the platform 20. In order to control the
inclination of the platform 20, a sensor (not shown) for detecting the
inclination of the platform 20 is disposed at a proper place of the
treadmill 40 so as to control the travel change of the lifting motor 10.
Accordingly, a practical adjustment of the inclination of the platform 20
is achieved. However, this conventional lifting motor 10 must employ an
external sensor to provide the measuring signals of the transmission
travel change. Thereafter, the transmission may be controlled.

[0005]However, the sensor for detecting the travel change is mounted at
the external side of the lifting motor 10, thereby taking much time and
efforts for the installation. Moreover, the detection is easily affected
by the external environment, thereby decreasing the measuring precision.
In addition, it is easily damaged to affect the service life. Thus, it
requires further improvements.

SUMMARY OF THE INVENTION

[0006]An object of the invention is to provide an apparatus for detecting
the travel of a lifting motor that permits a precise measurement of the
transmission travel.

[0007]Another object of the invention is to provide an apparatus for
detecting the travel of a lifting motor that includes a built-in sensor.
In this way, the influence and the damage by the external environment may
be avoided for prolonging the service life. Moreover, an integral
arrangement and a convenient installation are ensured

[0008]In order to achieve the above-mentioned objects, an apparatus for
detecting the travel of a lifting motor includes:

[0009]a) a housing consisting of a front housing and a rear housing;

[0010]b) a transmission unit positioned within the housing and having a
reduction gearset and a transmission gear meshed with the reduction
gearset;

[0011]c) a motor positioned at the external side of the housing, a driving
shaft of the motor being extended into the housing for driving the
reduction gearset;

[0012]d) a threaded rod passing through the housing and threadedly coupled
with the transmission gear; and

[0013]e) a fixing sleeve mounted at the external side of the housing and
fitting over one end of the threaded rod;

[0014]wherein the transmission unit includes at least one magnet at one of
the gears made of non-permeable material, and wherein the magnets are
rotated clockwise or counterclockwise with the non-permeable gear when
the transmission unit is driven by the motor in rotation, and wherein the
number of rotation will be detected by a magnetic sensor disposed at the
housing through the magnetic line of force generated by the magnet,
whereupon the detection signals will be transmitted to a
travel-calculation unit for measuring the linear displacement distance
(travel) of the threaded rod in axial direction.

[0015]According to the invention, the non-permeable gear is either the
transmission gear or the reduction gearset of the transmission unit.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]The accomplishment of this and other objects of the invention will
become apparent from the following descriptions and its accompanying
figures of which:

[0017]FIG. 1 is a perspective view of a lifting motor for a conventional
treadmill;

[0018]FIG. 2 is an exploded perspective view of an apparatus in accordance
with the invention;

[0019]FIG. 3 is a top view of the apparatus in accordance with the
invention after assembly;

[0020]FIG. 4 is a cutaway view of the apparatus in accordance with the
invention;

[0021]FIG. 5 is a perspective view of a transmission gear fitted with
magnets in accordance with the invention;

[0022]FIG. 6 is a perspective view of a reduction gearset fitted with
magnets in accordance with the invention;

[0023]FIG. 7 is a cross-sectional view taken along the line 7-7 in FIG. 4,
showing that the magnets are positioned in the transmission gear; and

[0024]FIG. 8 is a schematic drawing of the invention, showing that the
magnets are positioned in the reduction gearset.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0025]First of all, referring to FIGS. 2 through 8, an apparatus for
detecting the travel of a lifting motor in accordance with the invention
includes a housing 50, a transmission unit 60, a motor 53, a threaded rod
55, and a fixing sleeve 54.

[0026]The housing 50 consists of a front housing 51 and a rear housing 52.
The housing 50 is made of metal or plastic material.

[0027]The transmission unit 60 is positioned within the housing 50 and
includes a reduction gearset 62 and a transmission gear 61 meshed with
the reduction gearset 62.

[0028]The motor 53 is positioned at the external side of the housing 50.
According to this embodiment, the motor 53 is mounted on the rear housing
52. Moreover, a driving shaft 531 of the motor 53 is extended into the
housing 50 for driving the reduction gearset 62.

[0029]The threaded rod 55 passes through the housing 50 and is threadedly
coupled with the transmission gear 61. According to this embodiment, the
center of the transmission gear 61 is provided with a thread 611 for a
threaded connection with the threaded rod 55. In this way, a transmission
between a threaded rod and a threaded sleeve takes place. In other words,
the threaded rod 55 is linearly moved in the axial direction when the
transmission gear 61 is rotated by the reduction gearset 62.

[0030]The fixing sleeve 54 is mounted at the external side of the housing
50 and fits over one end of the threaded rod 55. According to this
embodiment, the fixing sleeve 54 is disposed on the rear housing 52 and
arranged parallel to the motor 53. The fixing sleeve 54 is employed for
providing a room when the threaded rod 55 is axially moved. In addition,
the fixing sleeve 54 includes a pivotal hole 541 at the rear end thereof
for a pivotal connection to an treadmill.

[0031]The object of the invention is to calculate the axial displacement
or the lifting transmission travel of the threaded rod 55. As a result,
the primary features of the invention are detailed as follows:

[0032]The transmission unit 60 includes at least a magnet 70 on a
non-permeable gear 70. The non-permeable material includes aluminum,
copper, or plastic material. The permeable material like iron should not
be employed since the magnetic line of force of the magnet 70 may be
affected.

[0033]An embodiment of the invention is shown in FIGS. 5 and 7. More than
one magnet 70 is positioned at the transmission gear 61 of the
transmission unit 60. The transmission gear 61 is driven by the reduction
gearset 62 so that the rotation thereof is decelerated. Moreover, it has
a larger diameter so that it is a preferred embodiment, but should not be
restricted thereto. According to another embodiment shown in FIGS. 6 and
8, the magnets 70 are positioned at the reduction gearset 62.

[0034]The transmission gear 61 and the reduction gearset 62 fitted with
the magnets 70 are made of non-permeable material. Therefore, the
magnetic line of force generated by the magnet 70 won't be interfered. As
shown in FIGS. 7 and 8, the magnets 70 are rotated clockwise or
counterclockwise with the transmission gear 61 or the reduction gearset
62 made of non-permeable material when the transmission unit 60 is driven
by the motor 53 in rotation. The number of rotation will be detected by a
magnetic sensor 80 disposed at the housing 50 through the magnetic line
of force generated by the magnet 70. Then, the detection signals will be
transmitted via a cable 81 to a travel-calculation unit 90 for measuring
the linear displacement distance of the threaded rod 55 in axial
direction. The linear displacement distance stands for the transmission
travel.

[0035]According to this embodiment, the magnetic sensor 80 is selected
from a group consisting of a solenoid or a Hall-IC (integrated circuit).
The magnetic sensor 80 produces one measuring signal when the magnets 70
on the transmission gear 61 or on the reduction gearset 62 rotatingly
pass through the position of the magnetic sensor 80. One measuring signal
stands for one-fourth circle when four magnets 70 are mounted on the
transmission gear 61. In this way, the number of rotation of the
transmission gear 61 may be determined. As a result, the change of the
transmission travel of the threaded rod 55 is measured according to
preset parameters when the external travel-calculation unit 90 receives
the signal of the number of rotation of the transmission gear 61.
Moreover, the travel-calculation unit 90 may be installed at a console of
the treadmill and includes a display surface 91 and an operation
interface 92. In this way, the operator may conduct an adjustment
according to his needs at will. In other words, the inclination of the
treadmill's platform may be adjusted to achieve an operator-oriented
operation.

[0036]According to the invention, the magnets 70 built within the
non-permeable transmission unit 60 are employed for an accurate
measurement of the lifting travel by use of the rotational detection of
the magnetic line of force without the influence by the external
environment. Accordingly, a reliable operation is achieved. Moreover, the
complete structure is easily secured to the treadmill, thereby increasing
the practicalness of the product.

[0037]Many changes and modifications in the above-described embodiments of
the invention can, of course, be carried out without departing from the
scope thereof. Accordingly, to promote the progress in science and the
useful arts, the invention is disclosed and is intended to be limited
only by the scope of the appended claims.